Compressor housing, compressor and booster

Abstract

A compressor housing configured to rotatably house a compressor impeller having a hub and a plurality of vanes provided on an outer surface of the hub, the compressor housing including a shroud portion having a shroud surface curved in a convex shape in opposition to the plurality of vanes, and at least one injection hole provided in the shroud portion for injecting water or a mixed fluid of water and air toward the compressor impeller.

Description

Technical Field

[0001] The present invention relates to a compressor housing that houses a compressor impeller, a compressor having the compressor housing, and a booster.

[0002] This application claims priority based on Japanese Patent Application No. 2023-050109 filed with the Japan Patent Office on March 27, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] When the engine starts, less exhaust gas flows from the engine to the turbocharger, and due to the inertia of the turbocharger's rotating body, the turbocharger performs less work, resulting in a smaller amount of compressed air being delivered from the turbocharger to the engine. Therefore, black smoke is sometimes emitted from the engine. To suppress this black smoke emission and improve turbocharger efficiency by improving the turbocharger's load responsiveness (acceleration) during engine start-up, a method exists where compressed gas is injected into the impeller blades of the compressor impeller through injection holes located on an air guide tube in the compressor housing.

[0004] Patent document 1 describes a method for obtaining a target boost air pressure by supplying compressed air (compressed gas) to the impeller blades of a compressor impeller through multiple injection holes provided throughout the outer periphery of the compressor impeller in the turbocharger when the engine load is increased.

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 61-132721 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] As described in Patent Document 1, when compressed gas is injected near the outlet of the compressor impeller (the outer periphery of the compressor impeller), a large torque can be obtained to assist the rotation of the compressor impeller when the engine load is relatively small, such as during engine startup. Compared with the structure described in Patent Document 1, there is a requirement to further improve the load responsiveness (acceleration performance) of the turbocharger during engine startup.

[0010] In view of the above, the object of at least one embodiment of the present invention is to provide a compressor housing capable of effectively supporting the rotation of a compressor impeller, a compressor having the compressor housing, and a booster.

[0011] means for solving technical problems

[0012] At least one embodiment of the present invention relates to a compressor housing configured to rotatably accommodate a compressor impeller having a hub and a plurality of blades disposed on the outer surface of the hub, wherein the compressor housing comprises:

[0013] The protective cover has a protective cover surface that is bent into a convex shape in a manner opposite to the plurality of blades; and

[0014] At least one injection hole is provided in the shroud for spraying water or a mixture of water and air toward the compressor impeller.

[0015] The compressor according to at least one embodiment of the present invention includes the compressor housing and the compressor impeller.

[0016] The booster according to at least one embodiment of the present invention includes the compressor.

[0017] Invention Effects

[0018] According to at least one embodiment of the present invention, a compressor housing capable of effectively supporting the rotation of a compressor impeller, a compressor having the compressor housing, and a booster are provided. Attached Figure Description

[0019] Figure 1 This is a schematic structural diagram that represents the structure of an engine system equipped with a turbocharger according to one embodiment of the present invention.

[0020] Figure 2 This is a schematic cross-sectional view along the central axis of the turbocharger according to one embodiment of the present invention.

[0021] Figure 3 This is a schematic cross-sectional view along the central axis of the compressor side of the turbocharger according to one embodiment of the present invention.

[0022] Figure 4 This is an explanatory diagram illustrating the configuration of the injection holes in one embodiment of the present invention. Detailed Implementation

[0023] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the constituent parts described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0024] (Engine system)

[0025] Figure 1This is a schematic structural diagram illustrating the structure of an engine system 1 equipped with a turbocharger 2 according to one embodiment of the present invention. The turbocharger 2 according to some embodiments of the present invention is mounted on, for example... Figure 1 The engine system 1 shown has an engine 11.

[0026] like Figure 1 As shown, the engine system 1 includes: an engine (engine body) 11 configured to generate power by burning fuel internally; a combustion gas supply line 12 for compressing and supplying combustion gases supplied to the engine 11; and a turbocharger 2 including a compressor (centrifugal compressor) 21 disposed on the combustion gas supply line 12, and a cooler (intercooler) 13 disposed downstream of the compressor 21 on the combustion gas supply line 12. The compressor 21 is configured to compress the combustion gases to increase their pressure. The cooler 13 is composed of a heat exchanger configured to cool the combustion gases heated and pressurized by the compressor 21. Examples of fuels for the engine 11 include gaseous fuels such as liquefied natural gas or liquid fuels such as fuel oil. Examples of combustion gases for the engine 11 include, for example, air.

[0027] The engine 11 includes: at least one cylinder 111; and at least one piston 112, which is reciprocally housed in the at least one cylinder 111 along the axial direction of the cylinder 111. The engine 11 has a combustion chamber 113 internally divided by the cylinder 111 and the piston 112.

[0028] The combustion gas supply line 12 includes: a flow path 12A for guiding combustion gas to the compressor 21; a flow path 12B for guiding combustion gas discharged from the compressor 21 to the cooler 13; and a flow path 12C for guiding combustion gas discharged from the cooler 13 to the combustion chamber 113. Flow paths 12A, 12B, and 12C are formed, for example, by piping. The combustion chamber 113 is configured to be connected to the flow path 12C downstream of the cooler 13 in the combustion gas supply line 12, from which combustion gas flows.

[0029] like Figure 1 As shown, the engine system 1 further includes: an exhaust pipe 14 for guiding exhaust gases emitted from the engine 11; and a fuel injection valve 15 configured to inject fuel into the engine 11. The turbocharger 2 also includes a turbine 22 disposed in the exhaust pipe 14. The exhaust pipe 14 includes a flow path 14A for guiding exhaust gases emitted from the combustion chamber 113 to the turbine 22. The flow path 14A is formed, for example, by piping. The combustion chamber 113 is connected to the flow path 14A of the exhaust pipe 14, discharging exhaust gases generated by combustion within the combustion chamber 113 into the exhaust pipe 14.

[0030] Fuel injection valve 15 is configured to inject fuel into either of the flow paths 12C formed inside the combustion chamber 113 or the engine 11. The fuel injected from fuel injection valve 15 into the combustion chamber 113 or flow path 12C mixes with combustion gases delivered to the combustion chamber 113 via flow path 12C, and then burns within the combustion chamber 113. The exhaust gases from combustion within the combustion chamber 113 are discharged to the outside of the engine system 1 through exhaust pipe 14.

[0031] (Supercharger)

[0032] Figure 2 This is a schematic cross-sectional view along the central axis CA of the turbocharger 2 according to one embodiment of the present invention. Figure 1 and Figure 2 As shown, the turbocharger 2 includes: the compressor 21 described above, which compresses the combustion gas (e.g., air) supplied to the engine 11; the turbine 22 described above, which is driven by the energy of the exhaust gas discharged from the engine 11; and a rotating shaft 23.

[0033] The compressor 21 includes: a compressor impeller 3 disposed in the combustion gas supply line 12; and a compressor housing 4 rotatably housing the compressor impeller 3. The turbine 22 includes: a turbine wheel 24 disposed in the exhaust line 14; and a turbine housing 25 rotatably housing the turbine wheel 24. The compressor impeller 3 is mechanically connected to one side of the rotating shaft 23, and the turbine wheel 24 is mechanically connected to the other side of the rotating shaft 23.

[0034] Combustion gas passing through compressor impeller 3 is guided to combustion chamber 113 of engine 11 via combustion gas supply line 12, and is supplied for combustion in combustion chamber 113 together with fuel injected from fuel injection valve 15. Exhaust gas generated by combustion in combustion chamber 113 is guided to turbine impeller 24 via exhaust line 14. Turbocharger 2 is configured to rotate turbine impeller 24 using the energy of exhaust gas discharged from engine 11. Compressor impeller 3 is mechanically connected to turbine impeller 24 via rotating shaft 23, and therefore rotates in conjunction with the rotation of turbine impeller 24. Turbocharger 2 is configured to compress combustion gas passing through compressor impeller 3 by rotating compressor impeller 3, increasing the density of the combustion gas and delivering it to engine 11.

[0035] like Figure 2 As shown, the turbocharger 2 also includes: a bearing 26 that rotatably supports the rotating shaft 23 between the compressor impeller 3 and the turbine impeller 24; and a bearing housing 27 that is disposed between the compressor housing 4 and the turbine housing 25 to support the bearing 26.

[0036] The compressor housing 4 includes: a gas inlet flow path forming portion 42, forming a gas inlet flow path 41 extending axially along the rotation axis 23 and used to guide combustion gas to the compressor housing 4; and a vortex flow path forming portion 44, forming a vortex-shaped vortex flow path 43 disposed on the outer peripheral side of the compressor impeller 3 and extending circumferentially along the rotation axis 23. The turbine housing 25 includes: a vortex flow path forming portion 252, forming a vortex-shaped vortex flow path 251 disposed on the outer peripheral side of the turbine impeller 24 and extending circumferentially along the rotation axis 23; and an exhaust gas discharge flow path forming portion 254, forming an exhaust gas discharge flow path 253 extending axially along the rotation axis 23 and used to discharge exhaust gas that has passed through the turbine impeller 24.

[0037] (compressor)

[0038] Figure 3 This is a schematic cross-sectional view along the central axis CA of the compressor 21 side of the booster 2 according to one embodiment of the present invention. Figure 3 As shown, the compressor impeller 3 has: a hub 31 mounted on the aforementioned side of the rotating shaft 23; and a plurality of blades 33 protruding from the outer surface 32 of the hub 31. The hub 31 is mechanically fixed to the aforementioned side of the rotating shaft 23, so the hub 31 or the plurality of blades 33 can rotate integrally with the rotating shaft 23. The compressor impeller 3 is configured such that it extends axially from the central axis CA of the compressor impeller 3 (booster 2) on one side. Figure 3 The centrifugal impeller, which directs combustion gas (from the left side of the center) to the radially outer side of the turbocharger 2, is configured to... In the illustrated embodiment, the outer surface 32 of the hub 31 is formed such that as it moves from the aforementioned side in the axial direction of the turbocharger 2 towards the other side... Figure 3 (Right side) and the concave curve increases in distance from the central axis CA of the booster 2 (rotating shaft 23).

[0039] like Figure 3 As shown, the compressor housing 4 also includes a shroud (air guide tube) 46 having a convexly curved shroud surface 45 that faces the plurality of blades 33 with a gap between it and the shroud surface 45. Each of the plurality of blades 33 has a blade tip edge 34 extending from the outer peripheral end of the leading edge 331 of the blade 33 to the outer peripheral end of the trailing edge and facing the shroud surface 45 with a gap between them. The shroud surface 45 and the blade tip edge 34 are respectively formed in a curved shape that increases in distance from the central axis CA of the turbocharger 2 as it moves from one side of the turbocharger 2 toward the other side in the axial direction.

[0040] In the illustrated embodiment, the shroud 46 is configured in a cylindrical shape to surround the compressor impeller 3. The inner and outer diameters of the shroud 46 increase toward the other side of the compressor 2 along the axial direction, which is closer to the other side than the leading edge 331 of the compressor impeller 3.

[0041] like Figure 3 As shown, the compressor housing 4 has at least one injection hole 5, which is disposed in the aforementioned protective cover 46 and is used to spray water W or a water-air mixture MF toward the compressor impeller 3. Each of the at least one injection hole 5 is configured to spray water W or the water-air mixture MF toward the negative pressure surface (blade surface) 330 of the blades 33 of the compressor impeller 3. The negative pressure surface 330 is located on the extension line of the central axis LA of each of the at least one injection hole 5. The water W or the mixture MF sprayed from the at least one injection hole 5 collides with the negative pressure surface 330, thereby supporting the rotation of the compressor impeller 3.

[0042] In the illustrated embodiment, the cylindrical nozzle 50 is inserted into a through hole 461 that extends from the outer peripheral surface of the shroud 46 to its inner peripheral surface (shroud surface 45). The aforementioned spray hole 5 is formed on the inner surface of the cylindrical nozzle 50. Figure 3 In the embodiment shown, the through hole 461 extends linearly through the shroud portion 46. The injection hole 5 communicates with the space inside the compressor housing 4 that accommodates the compressor impeller 3.

[0043] In the illustrated embodiment, an annular space 47 is formed between the outer peripheral surface of the shroud portion 46 and the vortex flow path forming portion 44, and the fluid inlet pipe 51 passes through the annular space 47. The end of the nozzle 50 separated from the space housing the compressor impeller 3 is connected to one end of the fluid inlet pipe 51 for introducing the spray target, i.e., water W or mixed fluid MF, into the injection hole 5. Water W or mixed fluid MF is introduced from the fluid inlet pipe 51 into the injection hole 5. Furthermore, the fluid inlet pipe 51 is not limited to the structure described above or the structure described later, as long as it can guide water W or mixed fluid MF to the injection hole 5.

[0044] Based on the above structure, water is an incompressible fluid and does not cause throttling, therefore no flow restriction is needed to prevent throttling. Therefore, compared to the case of air injection, the flow rate of water W or the mixed fluid MF injected from at least one injection hole 5 can be increased. Compared to the case of air injection, by injecting water W or the mixed fluid MF towards the compressor impeller 3, the rotation of the compressor impeller 3 can be effectively supported, thereby improving the tracking accuracy of the compressor impeller 3's rotation relative to the rotation of the engine 11.

[0045] Furthermore, according to the above structure, water sprayed from at least one of the above-mentioned injection holes 5 can cool the gas supplied through the compressor impeller 3, i.e., the combustion gas, thereby improving the efficiency of the compressor 21 or the engine system 1 equipped with the compressor 21.

[0046] Furthermore, the present invention is applicable to any situation where the engine 11 operates on liquid fuel or gaseous fuel, but it is particularly preferred when operating on gaseous fuel where the load variation of the engine 11 is relatively large. Examples of engines 11 that operate on gaseous fuel include, for example, marine main engine engines or power generation engines installed on land.

[0047] In some implementations, such as Figure 3 As shown, the aforementioned plurality of injection holes 5 are respectively configured to inject a mixed fluid MF or water W onto the outer periphery of the compressor impeller 3. Figure 3 In the illustrated embodiment, the position of the central axis CA of the compressor impeller 3 is defined as 0% in the radial direction, and the position 35 of the maximum outer diameter of the hub 31 is defined as 100%. The aforementioned plurality of injection holes 5 are respectively located on the outer periphery of the compressor impeller 3, that is, at a radial position of 50% to 100% of the compressor impeller 3, where a straight line extending the central axis LA intersects the negative pressure surface (blade surface) 330. Furthermore, it is preferable that the straight line extending the central axis LA intersects the negative pressure surface 330 at a radial position of 60% to 100% of the compressor impeller 3.

[0048] According to the above structure, compared with the case of spraying mixed fluid MF or water W onto the inner circumference of the compressor impeller 3, by spraying mixed fluid MF or water W onto the outer circumference of the compressor impeller 3, the torque acting on the compressor impeller 3 can be increased through the collision of mixed fluid MF or water W, and the rotation of the compressor impeller 3 can be effectively supported.

[0049] Figure 4 This is an explanatory diagram illustrating the configuration of the injection hole 5 in one embodiment of the present invention. Figure 4 The state is roughly shown as viewed from one side of the compressor impeller 3 along its axial direction. Figure 4 The symbol R in the figure indicates the rotation direction of the compressor impeller 3. In some embodiments, such as Figure 4 As shown, the plurality of injection holes 5 are configured to inject either a mixed fluid MF or water W along a tangential direction T relative to the rotation direction R of the compressor impeller 3. The plurality of injection holes 5 inject either the mixed fluid MF or water W along a direction downstream of the rotation direction R of the compressor impeller 3 within the tangential direction T relative to the rotation direction R of the compressor impeller 3.

[0050] According to the above structure, by injecting the mixed fluid MF or water W along the tangential direction T relative to the rotation direction R of the compressor impeller 3, the impact force of the mixed fluid MF or water W effectively acts on the compressor impeller 3, thus effectively supporting the rotation of the compressor impeller 3.

[0051] In some implementations, such as Figure 1 and Figure 4 As shown, the plurality of injection holes 5 include at least one water injection hole 6, which is configured to inject only water W or water W in the mixed fluid MF onto the compressor impeller 3. In one embodiment, all of the plurality of injection holes 5 may be water injection holes 6.

[0052] Based on the above structure, water W is an incompressible fluid and does not cause throttling; therefore, flow restriction is not required to prevent throttling. Compared to the case of injecting a mixed fluid MF, injecting water W towards the compressor impeller 3 effectively supports the rotation of the compressor impeller 3.

[0053] In some implementations, such as Figure 1 and Figure 4 As shown, the plurality of injection holes 5 include at least one mixed fluid injection hole 7, which is configured to inject only water W or the mixed fluid MF from the mixed fluid MF onto the compressor impeller 3. In one embodiment, all of the plurality of injection holes 5 may be mixed fluid injection holes 7.

[0054] According to the above structure, by injecting the mixed fluid MF towards the compressor impeller 3, the water W contained in the mixed fluid MF can be more widely diffused, thus effectively cooling the gas supplied through the compressor impeller 3. Furthermore, compared to injecting water W, the discharge volume can be reduced when the mixed fluid MF is injected towards the compressor impeller 3.

[0055] In some implementations, such as Figure 1 and Figure 4 As shown, the aforementioned at least one injection hole 5 includes a plurality of injection holes 5 spaced apart circumferentially on the compressor impeller 3. The plurality of injection holes 5 include: at least one water injection hole 6 configured to inject only water W or water W in the mixed fluid MF onto the compressor impeller 3; and at least one mixed fluid injection hole 7 configured to inject only water W or mixed fluid MF in the mixed fluid MF onto the compressor impeller 3.

[0056] According to the above structure, by spraying water W from the water injection hole 6 toward the compressor impeller 3, the rotation of the compressor impeller 3 can be effectively supported. Furthermore, by spraying mixed fluid MF from the mixed fluid injection hole 7 toward the compressor impeller 3, the gas supplied through the compressor impeller 3 can be effectively cooled.

[0057] In some implementations, such as Figure 4As shown, the aforementioned at least one water injection hole 6 includes: a first water injection hole 6A; and a second water injection hole 6B, disposed at a position opposite to the first water injection hole 6A in the circumferential direction, separated from the central axis CA of the compressor impeller 3. The aforementioned at least one mixed fluid injection hole 7 includes: a first mixed fluid injection hole 7A, disposed between the first water injection hole 6A and the second water injection hole 6B in the circumferential direction of the compressor impeller 3; and a second mixed fluid injection hole 7B, disposed at a position opposite to the first mixed fluid injection hole 7A in the circumferential direction, separated from the central axis CA of the compressor impeller 3. Furthermore, in Figure 4 In the embodiment shown, the compressor housing 4 has two water injection holes 6A and 6B and two mixed fluid injection holes 7A and 7B, but the number of water injection holes 6 or mixed fluid injection holes 7 provided by the compressor housing 4 is not limited to this.

[0058] like Figure 4 As shown, when viewed from one side of the compressor impeller 3 along its axial direction, or when the circumferential position of the central axis LA of a certain injection hole 5 is defined as 0°, the position opposite to the central axis CA in the circumferential direction refers to the position within the circumferential range of 90° or more and 270° or less.

[0059] exist Figure 4 In the illustrated embodiment, when viewed from one side along the axial direction of the compressor impeller 3, the circumferential position of the central axis LA of the first water jet hole 6A is defined as 0°, the rotation direction R of the compressor impeller 3 is defined as positive, and the circumferential angle θ is defined. The second water jet hole 6B is disposed within a circumferential range of 90° or more and 270° or less. Preferably, the second water jet hole 6B is disposed within a circumferential range of 120° or more and 240° or less, and more preferably within a circumferential range of 150° or more and 210° or less.

[0060] The first mixing fluid injection hole 7A is preferably disposed within a circumferential range of 30° or more and 150° or less, and more preferably within a circumferential range of 60° or more and 120° or less. The second mixing fluid injection hole 7B is preferably disposed within a circumferential range of 210° or more and 330° or less, and more preferably within a circumferential range of 240° or more and 300° or less.

[0061] According to the above structure, by arranging the water jet holes 6A and 6B and the mixed fluid jet holes 7A and 7B relatively evenly in the circumferential direction, it is possible to suppress the collision force of the mixed fluid or water from acting biasedly on a portion of the circumferential direction of the compressor impeller 3, and thus the rotation of the compressor impeller 3 can be effectively supported by the aforementioned collision force.

[0062] (Water or mixed fluid supply system)

[0063] exist Figure 1In the illustrated embodiment, the other end of the fluid inlet pipe 51 is connected to a water storage tank 52, which serves as the supply source for water W. The water storage tank 52 is configured to store, for example, water at room temperature (0°C to 40°C). A pump 53 is provided on the fluid inlet pipe 51 to increase the pressure of the water W flowing through it. The water W ejected from the injection port 5 is pressurized by the pump 53. A valve may be provided on the fluid inlet pipe 51 to control the supply of water W from the water storage tank 52.

[0064] The fluid inlet pipe 51 branches into multiple pipes 51A and 51B at a branch point P1 located further away from the pump 53. Among the multiple branched pipes 51A and 51B, the pipe connected to the water jet hole 6 is designated as the water inlet pipe 51A, and the pipe connected to the mixed fluid jet hole 7 is designated as the mixed fluid inlet pipe 51B. The mixed fluid inlet pipe 51B is designed to merge with the compressed air inlet pipe 54, which flows with compressed air A, at the confluence point P2.

[0065] Water W is introduced into the water jet hole 6 via a branch P1 closer to the pump 53 and water inlet pipe 51A. A mixed fluid MF formed by mixing water W and compressed air A is introduced into the mixed fluid jet hole 7 via a mixed fluid inlet pipe 51B and compressed air inlet pipe 54, both closer to the pump 53 than the branch P1 of the fluid inlet pipe 51.

[0066] Alternatively, the upstream side of the compressed air inlet pipe 54 can be connected to the flow path 12C, and a portion of the air flowing through the flow path 12C is drawn into the compressed air inlet pipe 54. In this case, the air flowing through the flow path 12C is pressurized in the compressor 21, thus eliminating the need for a pump to deliver the compressed air A to the mixing fluid injection port 7. Furthermore, the water tank 52 can be configured to store engine cooling water for cooling the engine 11, or the fluid inlet pipe 51 can be configured to share a pipe from the water tank 52 to the branch P3 between the water tank 52 and the cooling water inlet pipe 55 for introducing engine cooling water from the water tank 52 to the engine 11.

[0067] (Water discharge system)

[0068] The cooler 13 is equipped with a mechanism for discharging water generated by the condensation of combustion gases. If the water W ejected from the injection hole 5 flows to a downstream side (engine 11 side) than the compressor impeller 3, it is recycled into the cooler 13.

[0069] like Figure 3As shown, the compressor housing 4 may have a recess 48 formed on the lower side of the cover portion 46 in the vertical direction, which is recessed downwards and capable of storing water W. A water discharge hole 49 may be formed in the recess 48, extending from the lower side of the recess 48 in the vertical direction to the outer surface of the compressor housing 4. Water W ejected from the injection hole 5 falls from the compressor impeller 3 and is stored in the recess 48. The water W stored in the recess 48 is discharged to the outside of the compressor housing 4 through the water discharge hole 49.

[0070] like Figure 1 As shown, in some embodiments, the booster 2 includes a compressor 21, which includes the compressor impeller 3 and compressor housing 4 described above.

[0071] According to the above structure, by spraying water W or a mixed fluid MF towards the compressor impeller 3, the rotation of the compressor impeller 3 can be effectively supported, thus improving the efficiency of the compressor 21. Furthermore, by spraying water W towards the compressor impeller 3, the supply air passing through the compressor impeller 3 can be cooled, thus improving the efficiency of the compressor 21. By improving the efficiency of the compressor 21, the efficiency of the booster 2 can be improved.

[0072] In this specification, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" indicating relative or absolute configuration not only refer to such configuration in a strict sense, but also to the state of relative displacement in a manner that allows for tolerances or separation by angles or distances to achieve the same function.

[0073] For example, expressions such as "same," "equal," and "homogeneous" that indicate that things are in an equal state not only indicate the same state in a strict sense, but also indicate a state where there is a difference in the degree to which the same function can be obtained.

[0074] Furthermore, in this specification, the description of shape, such as quadrilateral or cylindrical shape, not only refers to the shape in a strict geometric sense, but also includes shapes such as concave or convex parts or chamfered parts within the range where the same effect can be obtained.

[0075] Furthermore, in this specification, expressions such as "possessing," "including," or "having" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0076] The present invention is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments or appropriate combinations thereof.

[0077] The contents described in some of the above embodiments can be understood, for example, as follows.

[0078] 1) In at least one embodiment of the present invention, the compressor housing 4 is configured to rotatably accommodate a compressor impeller 3 having a hub 31 and a plurality of blades 33 disposed on the outer surface 32 of the hub 31, the compressor housing 4 comprising:

[0079] The protective cover 46 has a protective cover surface 45 that is bent into a convex shape in a manner opposite to the plurality of blades 4; and

[0080] At least one injection hole 5 is provided in the shroud 46 for spraying water or a mixture of water and air toward the compressor impeller 3.

[0081] According to the structure described in 1), since water has a higher density than air, the energy required to rotate the compressor impeller 3 is less than that required for air. Furthermore, water is an incompressible fluid and does not cause throttling, thus eliminating the need for flow restrictions to prevent such throttling. Therefore, compared to the case of air injection, the flow rate of water or the mixed fluid injected from at least one injection hole 5 can be increased. Compared to the case of air injection, by injecting water or the mixed fluid toward the compressor impeller 3, the rotation of the compressor impeller 3 can be effectively supported, thereby improving the tracking accuracy of the compressor impeller 3's rotation relative to the rotation of the engine 11.

[0082] Furthermore, according to the structure described in 1), the water injected from at least one injection hole 5 can cool the air supplied through the compressor impeller 3, thereby improving the efficiency of the compressor 21 or the engine system 1 equipped with the compressor 21.

[0083] 2) In some embodiments, the compressor housing 4 described in 1) above,

[0084] The at least one injection hole 5 is configured to inject the mixed fluid or the water onto the outer periphery of the compressor impeller 3.

[0085] According to the structure described in 2), compared with the case of spraying mixed fluid or water onto the inner circumference of the compressor impeller 3, by spraying mixed fluid or water onto the outer circumference of the compressor impeller 3, the torque acting on the compressor impeller 3 can be increased through the collision of the mixed fluid or water, and the rotation of the compressor impeller 3 can be effectively supported.

[0086] 3) In some embodiments, the compressor housing 4 described in 1) or 2) above,

[0087] The at least one injection hole 5 is configured to inject the mixed fluid or the water along a tangential direction T relative to the rotation direction R of the compressor impeller 3.

[0088] According to the structure described in 3), by spraying the mixed fluid or water along the tangential direction T relative to the rotation direction R of the compressor impeller 3, the collision force of the mixed fluid or water is effectively applied to the compressor impeller 3, thus effectively supporting the rotation of the compressor impeller 3.

[0089] 4) In some embodiments, the compressor housing 4 described in any one of 1) to 3) above,

[0090] The at least one injection hole 5 includes at least one water injection hole 6, which is configured to inject only the water or the water in the mixed fluid onto the compressor impeller 3.

[0091] Based on the structure described in 4) above, since the density of water is greater than that of the mixed fluid, the energy required to rotate the compressor impeller 3 is reduced. Compared to the case of spraying the mixed fluid, spraying water toward the compressor impeller 3 can effectively support the rotation of the compressor impeller 3.

[0092] 5) In some embodiments, the compressor housing 4 described in any one of 1) to 3) above,

[0093] The at least one injection hole 5 includes at least one mixed fluid injection hole 7, which is configured to inject only the water or the mixed fluid in the mixed fluid onto the compressor impeller 3.

[0094] According to the structure described in 5) above, by injecting the mixed fluid toward the compressor impeller 3, the water contained in the mixed fluid can be more widely diffused, thus effectively cooling the air supplied through the compressor impeller 3. Furthermore, compared to the case of injecting water, the discharge volume can be reduced when injecting the mixed fluid toward the compressor impeller 3.

[0095] 6) In some embodiments, the compressor housing 4 as described in any one of 1) to 3) above,

[0096] The at least one injection hole 5 includes a plurality of injection holes 5 arranged at intervals in the circumferential direction of the compressor impeller 3.

[0097] The plurality of injection holes 5 include:

[0098] At least one water jet hole 6 is configured to spray only the water or the water in the mixed fluid onto the compressor impeller 3; and

[0099] At least one mixed fluid injection hole 7 is configured to inject only the water or the mixed fluid in the mixed fluid onto the compressor impeller 3.

[0100] According to the structure described in 6), by spraying water from the water injection hole 6 toward the compressor impeller 3, the rotation of the compressor impeller 3 can be effectively supported. Furthermore, by spraying a mixed fluid from the mixed fluid injection hole 7 toward the compressor impeller 3, the gas supplied through the compressor impeller 3 can be effectively cooled.

[0101] 7) In some embodiments, the compressor housing 4 described in 6) above,

[0102] The at least one water jet hole 6 includes:

[0103] First water jet hole 6A; and

[0104] The second water jet hole 6B is positioned circumferentially opposite the first water jet hole 6A, separated by the central axis CA of the compressor impeller 3.

[0105] The at least one mixed fluid injection hole 7 includes:

[0106] A first mixed fluid injection hole 7A is disposed between the first water injection hole 6A and the second water injection hole 6B in the circumferential direction; and

[0107] The second mixed fluid injection port 7B is disposed at a position opposite to the first mixed fluid injection port 7A in the circumferential direction, across the central axis CA of the compressor impeller 3.

[0108] According to the structure of 7) above, by arranging the water jet holes 6A and 6B and the mixed fluid jet holes 7A and 7B relatively evenly in the circumferential direction, it is possible to suppress the collision force of the mixed fluid or water from acting biasedly on a part of the circumferential direction of the compressor impeller 3, and thus the rotation of the compressor impeller 3 can be effectively supported by the aforementioned collision force.

[0109] 8) The compressor 21 according to at least one embodiment of the present invention comprises:

[0110] The compressor housing 4 as described in any one of 1) to 7) above; and

[0111] The compressor impeller 3.

[0112] According to the structure described in 8), by spraying water or a mixed fluid toward the compressor impeller 3, the rotation of the compressor impeller 3 can be effectively supported, thus improving the efficiency of the compressor 21. Furthermore, by spraying water toward the compressor impeller 3, the gas supplied through the compressor impeller 3 can be cooled, thus improving the efficiency of the compressor 21.

[0113] 9) The turbocharger 2 according to at least one embodiment of the present invention comprises:

[0114] The compressor 21 described in 8) above.

[0115] Based on the structure described in 9), by improving the efficiency of the compressor 21, the efficiency of the booster 2 can be improved.

[0116] Symbol Explanation

[0117] 1-Engine system, 2-Turbocharger, 3-Compressor impeller, 4-Compressor housing, 5-Injection port, 6, 6A, 6B-Water injection ports, 7, 7A, 7B-Mixed fluid injection ports, 11-Engine, 12-Combustion gas supply line, 13-Cooler, 14-Exhaust line, 15-Fuel injection valve, 21-Compressor, 22-Turbine, 23-Rotating shaft, 24-Turbine impeller, 25-Turbine housing, 26-Bearing, 27-Bearing base 31-Hub, 32-Outer surface, 33-Blade, 34-Blade tip edge, 45-Shield surface, 46-Shield section, 50-Nozzle, 51-Fluid inlet pipe, 51A-Water inlet pipe, 51B-Mixed fluid inlet pipe, 52-Water storage tank, 53-Pump, 54-Compressed air inlet pipe, 55-Cooling water inlet pipe, A-Compressed air, CA-Central shaft, LA-Central axis, MF-Mixed fluid, R-Direction of rotation, W-Water.

Claims

1. A compressor housing configured to rotatably accommodate a compressor impeller having a hub and a plurality of blades provided on an outer surface of the hub, the compressor housing comprising: a shroud portion having a shroud surface curved in a convex shape in a manner to oppose the plurality of blades; and at least one injection hole provided in the shroud portion for injecting a water or a mixed fluid of water and air toward the compressor impeller, wherein, when a position of a center axis of the compressor impeller is defined as 0% and a position of a maximum outer diameter of the hub is defined as 100% in a radial direction of the compressor impeller, the at least one injection hole is configured such that an extension line of a center axis of the at least one injection hole intersects with a negative pressure surface of the blade of the compressor impeller at a radial position of 50% or more and 100% or less of the compressor impeller.

2. The compressor housing according to claim 1, wherein the at least one injection hole is configured to inject the mixed fluid or the water in a tangential direction with respect to a rotational direction of the compressor impeller.

3. The compressor housing according to claim 1 or 2, wherein the at least one injection hole includes at least one water injection hole configured to inject only the water or the water in the mixed fluid onto the compressor impeller.

4. The compressor housing according to claim 1 or 2, wherein the at least one injection hole includes at least one mixed fluid injection hole configured to inject only the mixed fluid or the mixed fluid in the water onto the compressor impeller.

5. The compressor housing according to claim 1 or 2, wherein a lower side in a vertical direction of the shroud portion has a recessed portion recessed toward a vertically lower side, and a water discharge hole extending from the recessed portion toward an outer surface of the compressor housing in the vertical direction of the lower side is formed in the recessed portion.

6. A compressor housing configured to rotatably accommodate a compressor impeller having a hub and a plurality of blades provided on an outer surface of the hub, the compressor housing comprising: a shroud portion having a shroud surface curved in a convex shape in a manner to oppose the plurality of blades; and at least one injection hole provided in the shroud portion for injecting a water or a mixed fluid of water and air toward the compressor impeller, wherein the at least one injection hole includes a plurality of injection holes arranged at intervals in a circumferential direction of the compressor impeller, the plurality of injection holes including: at least one water injection hole configured to inject only the water or the water in the mixed fluid onto the compressor impeller; and at least one mixed fluid injection hole configured to inject only the mixed fluid or the mixed fluid in the water onto the compressor impeller.

7. The compressor housing according to claim 6, wherein the at least one water injection hole includes: a first water injection hole; and a second water injection hole arranged at a position opposite to the first water injection hole with respect to the circumferential direction of the center axis of the compressor impeller, and the at least one mixed fluid injection hole includes: a first mixed fluid injection hole; and a second mixed fluid injection hole arranged at a position opposite to the first mixed fluid injection hole with respect to the circumferential direction of the center axis of the compressor impeller. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ a first mixed fluid injection hole arranged between the first water injection hole and the second water injection hole in the circumferential direction; and a second mixed fluid injection hole arranged at a position opposite to the first mixed fluid injection hole with respect to the circumferential direction of the central axis of the compressor impeller.

8. A compressor housing configured to rotatably accommodate a compressor impeller having a hub and a plurality of blades provided on an outer surface of the hub, the compressor housing comprising: a shroud portion having a shroud surface curved in a convex shape in a manner to oppose the plurality of blades; and at least one injection hole provided in the shroud portion for injecting water or a mixed fluid of water and air toward the compressor impeller, the rotation of the compressor impeller being assisted by the water or the mixed fluid injected colliding with a negative pressure surface of the blades, a recessed portion recessed toward a vertically lower side on a vertical direction of the shroud portion is provided on a lower side in the vertical direction of the shroud portion, a water discharge hole extending along from the recessed portion toward the outer surface of the compressor housing on the vertically lower side in the vertical direction is formed in the recessed portion.

9. A compressor comprising: the compressor housing according to any one of claims 1, 2, 6, 7, or 8; and the compressor impeller.

10. A supercharger comprising the compressor according to claim 9.

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